Python dictionaries provide built-in methods to add, update, remove, and access key-value pairs.
update()
The update() method updates existing values or adds new key-value pairs.
Syntax
dictionary_name.update({key: value})
Example
student = {
"name": "John",
"age": 20
}
student.update({"age": 21})
print(student)
Output:
{'name': 'John', 'age': 21}
pop()
The pop() method removes a specified key and returns its value.
Syntax
dictionary_name.pop(key)
Example
student = {
"name": "John",
"age": 20
}
student.pop("age")
print(student)
Output:
{'name': 'John'}
popitem()
The popitem() method removes the last inserted item.
Syntax
dictionary_name.popitem()
Example
student = {
"name": "John",
"age": 20
}
student.popitem()
print(student)
Output:
{'name': 'John'}
clear()
The clear() method removes all items from a dictionary.
Syntax
dictionary_name.clear()
Example
student = {
"name": "John",
"age": 20
}
student.clear()
print(student)
Output:
{}
copy()
The copy() method creates a copy of a dictionary.
Syntax
dictionary_name.copy()
Example
student = {
"name": "John",
"age": 20
}
new_student = student.copy()
print(new_student)
Output:
{'name': 'John', 'age': 20}
setdefault()
The setdefault() method returns the value of a key. If the key does not exist, it inserts the key with the specified value.
Syntax
dictionary_name.setdefault(key, default_value)
Example
student = {
"name": "John"
}
student.setdefault("age", 20)
print(student)
Output:
{'name': 'John', 'age': 20}
fromkeys()
The fromkeys() method creates a new dictionary from a sequence of keys.
Syntax
dict.fromkeys(keys, value)
Example
keys = ("name", "age", "city")
student = dict.fromkeys(keys, "Not Set")
print(student)
Output:
{'name': 'Not Set', 'age': 'Not Set', 'city': 'Not Set'}
Summary
update()updates or adds key-value pairs.pop()removes a specific key.popitem()removes the last inserted item.clear()removes all dictionary items.copy()creates a duplicate dictionary.setdefault()returns a value or creates a key if it does not exist.fromkeys()creates a new dictionary using a list of keys.